What are ASTM Grades?

ASTM standards define the specific manufacturing process of the material and determine the exact chemical composition of pipes, fittings and flanges, through percentages of the permitted quantities of carbon, magnesium, nickel, etc., and are indicated by "Grade".

For example, a carbon steel pipe can be identified with Grade A or B, a stainless-steel pipe with Grade TP304 or Grade TP321, a carbon steel fitting with Grade WPB etc..

Below you will find as an example 3 tables with chemical requirements for:

1. Flanges according to ASTM A182 Grade F304, F304L F316L
2. Pipes according to ASTM A312 Grade TP304, TP304L, TP3016L
3. Fittings according to ASTM A403 Grade WP304, WP304L, WP316L

Furthermore, a table with frequently used ASTM Grades, arranged on Pipes, Fittings, Flanges, Valves, Bolts & Nuts, which belong together as a group.

As you may be have noted, in the table below, ASTM A105 has no Grade. Sometimes ASTM A105N is described;
N stands not for Grade, but for normalized. Normalizing is a type of heat treatment, applicable to ferrous metals only. The purpose of normalizing is to remove the internal stresses induced by heat treating, casting, forming etc..

Chemical requirements composition, %

Flanges according to ASTM A182
Grade	C	Mn	P	S	Si	Ni	Cr	Mo
F304	0.08	2.0	0.045	0.030	1.0	8.0-11.0	18.0-20.0
F304L	0.030	2.0	0.045	0.030	1.0	8.0-13.0	18.0-20.0
F316L	0.030	2.0	0.045	0.030	1.0	10.0-15.0	16.0-18.0	2.0-3.0
Note: Grades F304, F304L, and F316L shall have a maximum Nitrogen content of 0.10%.
Pipes according to ASTM A312
Grade	C	Mn	P	S	Si	Cr	Ni	Mo
TP304	0.08	2.0	0.045	0.030	1.0	18.0-20.0	8.0-11.0
TP304L	0.035	2.0	0.045	0.030	1.0	18.0-20.0	8.0-13.0
TP316L	0.035	2.0	0.045	0.030	1.0	16.0-18.0	10.0-14.0	2.0-3.0
Note: For small diameter or thin walls or both, where many drawing passes are required, a Carbon maximum of 0.040% is necessary in grades TP304L and TP316L. Small outside diameter tubes are defined as those less than 0.50 in. [12.7 mm] in outside diameter and light wall tubes as those less than 0.049 in. [1.20 mm] in average wall thickness (0.044 in. [1.10 mm] in minimum wall thickness).
Fittings according to ASTM A403
Grade	C (1)	Mn (1)	P (1)	S (1)	Si (1)	Ni	Cr	Mo
WP304	0.08	2.0	0.045	0.030	1.0	8.0-11.0	18.0-20.0
WP304L	0.030 (2)	2.0	0.045	0.030	1.0	8.0-12.0	18.0-20.0
WP316L	0.030 (2)	2.0	0.045	0.030	1.0	10.0-14.0 (3)	16.0-18.0	2.0-3.0
Notes: (1) Maximum, unless otherwise indicated. (2) For small diameter or thin walls or both, where many drawing passes are required, a Carbon maximum of 0.040% is necessary in grades TP304L and TP316L. Small outside diameter tubes are defined as those less than 0.50 in. [12.7 mm] in outside diameter and light wall tubes as those less than 0.049 in. [1.20 mm] in average wall thickness (0.044 in. [1.10 mm] in minimum wall thickness). (3) On pierced tubing, the Nickel may be 11.0-16.0%.

Frequently used ASTM Grades
Material	Pipes	Fittings	Flanges	Valves	Bolts & Nuts
Carbon Steel	A106 Gr A	A234 Gr WPA	A105	A216 Gr WCB	A193 Gr B7 A194 Gr 2H
	A106 Gr B	A234 Gr WPB	A105	A216 Gr WCB
	A106 Gr C	A234 Gr WPC	A105	A216 Gr WCB
Carbon Steel Alloy High-Temp	A335 Gr P1	A234 Gr WP1	A182 Gr F1	A217 Gr WC1	A193 Gr B7 A194 Gr 2H
	A335 Gr P11	A234 Gr WP11	A182 Gr F11	A217 Gr WC6
	A335 Gr P12	A234 Gr WP12	A182 Gr F12	A217 Gr WC6
	A335 Gr P22	A234 Gr WP22	A182 Gr F22	A217 Gr WC9
	A335 Gr P5	A234 Gr WP5	A182 Gr F5	A217 Gr C5
	A335 Gr P9	A234 Gr WP9	A182 Gr F9	A217 Gr C12
Carbon Steel Alloy Low-Temp	A333 Gr 6	A420 Gr WPL6	A350 Gr LF2	A352 Gr LCB	A320 Gr L7 A194 Gr 7
	A333 Gr 3	A420 Gr WPL3	A350 Gr LF3	A352 Gr LC3
Austenitic Stainless Steel	A312 Gr TP304	A403 Gr WP304	A182 Gr F304	A182 Gr F304	A193 Gr B8 A194 Gr 8
	A312 Gr TP316	A403 Gr WP316	A182 Gr F316	A182 Gr F316
	A312 Gr TP321	A403 Gr WP321	A182 Gr F321	A182 Gr F321
	A312 Gr TP347	A403 Gr WP347	A182 Gr F347	A182 Gr F347

ASTM Materials

Pipes

• A106 = This specification covers carbon steel pipe for high-temperature service.
• A335 = This specification covers seamless ferritic alloy-steel pipe for high-temperature service.
• A333 = This specification covers wall seamless and welded carbon and alloy steel pipe intended for use at low temperatures.
• A312 = Standard specification for seamless, straight-seam welded, and cold worked welded austenitic stainless steel pipe intended for high-temperature and general corrosive service.

Fittings

• A234 = This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction.
• A420 = Standard specification for piping fittings of wrought carbon steel and alloy steel for low-temperature service.
• A403 = Standard specification for wrought austenitic stainless steel piping fittings.

Flanges

• A105 = This specification covers standards for forged carbon steel piping components, that is, flanges, fittings, Valves, and similar parts, for use in pressure systems at ambient and higher-temperature service conditions.
• A182 = This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and Valves and parts for high-temperature service.
• A350 = This specification covers several grades of carbon and low alloy steel forged or ring-rolled flanges, forged fittings and Valves for low-temperature service.

Valves

• A216 = This specification covers carbon steel castings for Valves, flanges, fittings, or other pressure-containing parts for high-temperature service and of quality suitable for assembly with other castings or wrought-steel parts by fusion welding.
• A217 = This specification covers steel castings, martensitic stainless steel and alloys steel castings for Valves, flanges, fittings, and other pressure-containing parts intended primarily for high-temperature and corrosive service.
• A352 = This specification covers steel castings for Valves, flanges, fittings, and other pressure-containing parts intended primarily for low-temperature service.
• A182 = This specification covers forged or rolled alloy and stainless steel pipe flanges, forged fittings, and Valves and parts for high-temperature service.

Bolds & Nuts

• A193 = This specification covers alloy and stainless steel bolting material for pressure vessels, Valves, flanges, and fittings for high temperature or high pressure service, or other special purpose applications.
• A320 = Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for Low-Temperature Service.
• A194 = Standard specification for nuts in many different material types.